Edit:Meant to address to all, not just Bill
In the original (late 50’s) side of the house I have a fuse box that was originally just below mast/meter on upstairs wall. In late 70’s a garage with breezeway between was added and SI was moved on to garage wall. A rather elaborate gutter and couple of disconnects with panel for garage was put in garage.
Later (99) added on, put in 400a service , added disc for new work. No changes to old except now fed from new service. All above bought by AHJ (including first sentence below).
Ridgid metal conduit then fed the old fuse panel with two hots and neutral using the pipe as egc. Someone added a small sub with four screw in fuses off lugs about 8″ from panel. I intend to replace this with a small Bryant panel I took out of a job.
The fuse panel is 100amp service protected by breaker ( the disconnect in the garage is a cartgridge fused disc also). I have a now unused pullout disconnect for the dryer that used to be next door but the small cart fuses only go to 30a.
I was considering using the new sub as a main and four 20a setup. Options seem to be use a double pole 30a for main and feed from the load side of fused disc or come off the lugs feeding the disc and go ahead and use dp 40 for main.
The old fuse panel does have a ground/bonding lug and isolated neutral bar. Was considering adding saddle ground clamp to the pipe (RMC) and adding a larger ground terminal strip to original box.
Shop will have a good bit of stuff but the largest load at any given time will be TS and DC probably max. Both currently running well off a couple of 20a ckts and 15a recpts. Was considering going 240 for them but not sure worth the efforts, they are about 30 ft from panel.
Your thoughts kind sir?
Bob
Edited 7/7/2008 12:00 am ET by rasconc
Replies
I would say that I have had 2 many beers, because I realy can't follow what you are wanting to do.
The problem is that I have not had any all day.
Maybe I need more before reading it?
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I did ramble on. Basically plan to replace a small sub panel of fuse type with a breaker type. Question is whether it makes sense to feed the new one from the load side of a 30A 240 dryer disconnect with a 30A main breaker in sub or feed it from the line side and use a 40A main in the sub. It is less than 1' from the main panel. Only offset enough to clear NM coming out of side and going vertical.
Other side issue was how egc is provided to the original fuse panel (using the ridgid metal conduit).
I was trying to lay the ground work for what all was there and what the panel was going to serve.
I think I used the random thought generator function on my computer. It may have required more than beer for proper insight (:-).
Edited 7/7/2008 7:19 am ET by rasconc
Well I am guessing from the fact that you said that you currently run TS and dust collector on 120 that you have a 1.5 hp contractors saw and 1 - 1 1/2 hp DC.In that case 30 amps at 240 is more than enough.But if you might ever want to get something like a 3 hp unisaw then it would be pushing it. Specially if there miight be power for heat and/or cooling from this panel.40 would give you a little more margin." feed it from the line side and use a 40A main in the sub"I am not following where "line side" of what is from.If there is no main disconnection in front of this them it would endup being one of the 6 allowed disconnects in one immediate area.For a sub-panel the limiting factor is the breaker for the feeder. The feeder wires need to be rated equal or more than the feeder.The sub-panel needs to be rated equal or more than the feeder breaker. And the main disconnect has to be rated equal or more than the feeder breaker.There is no need to replace the "main" in a sub-panel with a smaller breaker. However, some people think tht it is "better". Many less chance of confusion about how much power that can be drawn through that panel.About the grounding I am not sure what the issue is. Can't it be grounded through the conduit? Where the connection is an issue there are speical fittings for that purpose.See attached..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Maybe some pictures will help. 1 is kind of overview of what is there. 2 is closer pic of the disconnect I was talking about. 5 is the main fuse panel data. I was talking about feeding it from the lug at the top and not having protection in the fuse panel, just at the sub. Then I could get 40 amps/leg. The panel being replaced is the four fuse one in upper right.
11 and 12 are the replacement sub.
I checked the dc and it says 2hp, 24A/120-12A/240. Cranked it up and it did read steady 22.3A. May be worth converting to 240. The saw is Ridgid ts3612, 13A/120-6.5/240. Last saw I ever intend to buy. No further heat/cool off this sub, only for the shop additional recpt. This is not an added room/etc just recapturing some of the basement.
On the grounding I was just looking at beefing up the bond, did not want to unhook all incoming wires to use a bond bushing like you pictured, was going to use the saddle style so an to not depend on the two locknuts on the 1 1/2 rmc entry to panel, wish they had used hub adapter. They did the same at the other end of the conduit at the disconnect in the garage.
IIRC hub and nipple threaded connections serve as grounding but attachment by locknuts does not.
Edited 7/7/2008 11:27 am ET by rasconc
Ok. It is starting to made some sense.First of all that Bryant said suitable for use as service entrance if there is no more than 6 disconnects.That could mean just that panel if all of the breakers are 2 pole. You can use a 2 pole breaker to backfeed a panel as the main breaker. But to do that there has to be some kind of holddown that keeps the breaker from being removed. There might be one, but I don't see it.On the fuse panel the bottom rigth says Service Disconnet PC2. But I can't tell how that is wired.It looks like everything has to come through the top center fuse block which would be the main disconnect.With something as confusing and non-standard by today thoughts I would not like to see any thing more than the existing disconnect at the fuse panel. So run it through the dryer fuse block."On the grounding I was just looking at beefing up the bond, did not want to unhook all incoming wires to use a bond bushing like you pictured, was going to use the saddle style so an to not depend on the two locknuts on the 1 1/2 rmc entry to panel, wish they had used hub adapter."Sect 250.#### is a long one that covers ground electrode systems (ground rods and other types of electrodes), bonding, and equipment grounding conductors.I *think* that the threaded hub limitation is on parts of the system that form the bond(s) from the service neutral to the grounding electrode conductors. For equipment grounding conductors, which is what you have from the main panel to the sub lock nuts are OK. But there is a limitation on grounding through concentric ring knockouts. But I don't know if that if is just for bonding are also includes equipment grounding conductors..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
There is a dp breaker at the top of the fuse panel, shows 100 on each side. The center fuse block is for the range, it is pc1 in the diagram pic 5. The pc2 is the lower left fuse block for the water heater. Power comes out of the breaker and has two buss bars that go under the screw-in fuse section and feeds a couple of taps at the top of pc3 and pc3 which is the empty block in the pic 1.
The disc for it all would be the breaker so I think the count of six would not be an issue. The disc for the sub would be the pc3 block (old dryer). Probably would be best to convert the dc to 240, do a 20 or even 15 DP for it, and run a couple of 20A 120 ckts for the saw and other stuff.
I guess it was the concentric part that had me thinking about the egc. I looked and all involved are single hole, at first thought conc but it was the paint scraped by locknut. Out in the garage I am going to extend a wire from existing ground to the rmc at the disconnect so I do not have to dig through several boxes to examine how connections are made.
When we did the add-on the insp made me do a saddle clamp on the new part disconnect maybe because of poor fit of the conduit, they may have punched out one too many rings or something. (#17)
Shot a little better picture of the main fuse panel data sheet (pic 22) and the breaker (19). The garage kluge is #14, the feed to the fuse panel under discussion is on left, it's inards is #16. It appears that there is a screw hole in the bryant panel that could attach a holder for a breaker used as a main (#18). #23 is the attachment for the to be replaced sub panel.
>>>The problem is that I have not had any all day.LOL.Always remember those first immortal words that Adam said to Eve, “You’d better stand back, I don’t know how big this thing’s going to get.â€